1. Field of the Invention
The disclosed and claimed concept relates to respiratory interface devices for transporting a gas to and/or from an airway of a user, and, in particular, to a manifold assembly for a respiratory interface device.
2. Description of the Related Art
There are numerous situations where it is necessary or desirable to deliver a flow of breathing gas non-invasively to the airway of a patient, i.e., without intubating the patient or surgically inserting a tracheal tube in their esophagus. For example, it is known to ventilate a patient using a technique known as non-invasive ventilation. It is also known to deliver continuous positive airway pressure (CPAP) or variable airway pressure, which varies with the patient's respiratory cycle, to treat a medical disorder, such as sleep apnea syndrome, in particular, obstructive sleep apnea (OSA), or congestive heart failure.
Non-invasive ventilation and pressure support therapies involve the placement of a patient interface device including a mask component on the face of a patient. The mask component may be, without limitation, a nasal mask that covers the patient's nose, a nasal cushion having nasal prongs that are received within the patient's nares, a nasal/oral mask that covers the nose and mouth, or a full face mask that covers the patient's face. The patient interface device interfaces the ventilator or pressure support device with the airway of the patient, so that a flow of breathing gas can be delivered from a pressure/flow generating device to the airway of the patient. It is known to maintain such devices on the face of a wearer by a headgear having one or more straps adapted to fit over/around the patient's head. Because such patient interface devices are typically worn for an extended period of time, it is important for the headgear to maintain the mask component of the device in a tight enough seal against the patient's face without discomfort.
A number of known patient interface devices provide airflow to the patient through the headgear via one or more delivery conduits that warp around portions of the head as part of the headgear. That is, the headgear includes a tubing assembly with a manifold. The manifold is coupled to, and in fluid communication with, a delivery conduit. The delivery conduit is further coupled to, and in fluid communication with, the pressure/flow generating device. Such known patient interface devices, however, have a number of drawbacks.
For example, when a patient wearing a patient interface device moves, e.g. during sleep, forces that act on the delivery conduit are transferred to the manifold and on to the tubing assembly. As the tubes of the tubing assembly are in contact with the patient, and often in contact with the patient's face, any significant movement of the tubing assembly is likely to disturb the patient.
One construct structured to lessen the forces transferred to the patient incorporates rotational couplings at various locations, such as at the manifold. The rotational couplings allow the various conduits and tubes to rotate thereby absorbing the rotational forces. A rotational coupling, however, requires that the tube at the coupling between the manifold and the tubes be substantially circular. A manifold, as well as the tubes, with a circular cross section contacts the patient over a limited area. That is, only a small portion of a manifold coupling with a circular cross section contacts the patient. Such a limited area of contact concentrates stresses, such as, but not limited to, stress created by a lateral force action upon the manifold. Thus, while a manifold that includes rotational couplings with the delivery tubes absorbs rotational forces, such a configuration concentrates other forces.
Accordingly, a need exists for a manifold assembly that decouples portions of the manifold body from external forces applied to the delivery conduit. Further, a need exists for a manifold assembly that includes non-circular couplings to the delivery tubes that extend over the patient's head.